[is] 本帖最后由 HonestQiao 于 2026-5-5 19:38 编辑 [/i]在 双核独立运行 中M33核 和 M55核 已经能够各自独立闪烁 LED。本文在此基础上进一步实现双核间的数据通信由 M33核 每秒发送一个递增的计数器M55核 接收并打印到串口。通信框架选用rpmsg-lite它是 NXP 开源的轻量级 RPMsg 实现专门面向 MCU 级别的异构多核场景占用资源少、移植简单。PSoC E84 的 M33 与 M55 之间通过共享内存Shared Memory交换数据rpmsg-lite 负责管理 vring 描述符环和 buffer 池屏蔽底层细节。一、rpmsg-lite 简介与共享内存布局rpmsg-lite 的核心概念概念说明Master负责初始化共享内存中的 vring、desc 链表和 buffer 池。本例中由M33担任。Remote等待 Master 初始化完成后 attach 到已有 vring。本例中由M55担任。Endpoint通信端点通过src/dst地址路由消息。两端使用相同的 endpoint address本例为30。Virtqueue虚拟队列基于 virtio ring 实现分为 txtvq和 rxrvq。在 PSoC E84 上M33 与 M55 的共享内存区域由 BSP 预先分配共享内存基地址0x261C0000 共享内存大小 0x1000064KB​rpmsg-lite 会在该区域内自动放置两个 vringrvq tvq以及RL_BUFFER_COUNT个 payload buffer。为了安全起见我们在共享内存的末端0x261CF000放置一个启动握手标志sentinel用于解决 M55 和 M33 时序同步问题。二、工程准备在 双核独立运行 创建的两个工程基础上确保各自已经添加了rpmsg-lite软件包打开RT-Thread Settings在软件包中搜索并添加rpmsg-lite保存配置系统会自动下载并集成到packages/rpmsg-lite/目录两个工程都需要添加 rpmsg-lite。三、rpmsg-lite 通信机制在动手写代码之前先理解 rpmsg-lite 在两核之间的数据流转路径。这样遇到问题时才能定位是发不出去还是收不到。正常通信路径理想情况发送侧M33application: rpmsg_lite_send(data) - core: rpmsg_lite_format_message (写入共享内存 vring) - virtqueue_kick - vq_ring_notify_host - virtqueue_notify - platform_notify (触发 IPC 中断 - M55)​接收侧M55IPC ISR (收到中断) - env_isr - virtqueue_notification (处理 rvq) - rpmsg_lite_rx_callback - ept-rx_cb (用户回调: rpmsg_rx_callback) - RL_RELEASE (释放 buffer 回空闲池)​本教程的实际路径Polling workaroundPSoC E84 的platform_notify()依赖 IPC 中断而实际测试中发现这条路径不可靠M55 经常收不到中断。因此我们在两侧都启动轮询线程用主动调用virtqueue_notification()的方式替代被动等待中断[M33 Polling 线程] 每 20ms: virtqueue_notification(rvq) virtqueue_notification(tvq) | v 驱动 rvq 回调(处理 M55 的回复) tvq 回调(更新 link_state) [M55 Polling 线程] 每 20ms: virtqueue_notification(rvq) | v 驱动 rvq 回调 - rpmsg_lite_rx_callback - ept-rx_cb​启动时序与握手这是另一个关键点。正常 RPMsg 流程假设 Master 和 Remote 先后启动中间有足够时间让master_init完成。但 PSoC E84 上M55 内核被 M33 释放复位后启动速度极快M55 的main()可能在 M33 的rpmsg_lite_master_init()之前就运行到轮询线程此时共享内存还是上电随机值virtqueue_get_available_buffer()会读到垃圾avail-idx越界访问desc[]触发 hard fault解决在master_init全部完成后向共享内存末端写入一个 magic sentinelM55 在调用remote_init之前先 spin 等待这个 magic。这就是启动握手机制。整体通信架构图下面这张图展示了本文最终实现的双核通信全貌包含 Master/Remote 角色、共享内存布局、Polling 线程的位置以及启动握手的时序关系四、M33 端Master发送方关键设计M33 作为 Master承担以下职责初始化共享内存调用rpmsg_lite_master_init()零化 vring、建立 desc 空闲链表、填充 tx buffer 池。启动握手在master_init和create_ept全部成功后向0x261CF000写入 magic0xC0DEDA7A告知 M55内存已就绪。Polling 线程由于 PSoC E84 的 IPC 中断通知路径存在可靠性问题M33 与 M55 之间的 IPC notify 有时无法送达额外启动一个轮询线程每隔 20ms 主动调用virtqueue_notification()驱动 rvq 和 tvq 的回调确保接收和发送状态都能及时更新。发送循环每秒发送一次uint32_t counter使用 200ms 超时而非RL_DONT_BLOCK在 tx buffer 暂时耗尽时自动等待 M55 回收。完整代码#include rtthread.h #include rtdevice.h #include board.h #include rpmsg_lite.h #include virtqueue.h #define LED_PIN_B GET_PIN(16, 5) #define RPMSG_LITE_SHMEM_BASE ((void *)0x261C0000) #define RPMSG_LITE_SHMEM_SIZE (0x10000) #define RPMSG_LITE_LINK_ID RL_PLATFORM_PSE84_M33_M55_LINK_ID #define RPMSG_LITE_EPT_ADDR (30U) /* Boot-handshake sentinel placed near the end of the shared region (well * outside the area used by rpmsg-lite vrings payload buffers). The master * writes RPMSG_HANDSHAKE_MAGIC ONLY after master_init has zeroed the vrings, * built the desc free-list and filled the tx-buffer pool. The remote side * spin-waits on this magic before doing anything that touches the rings, * otherwise it would read garbage out of un-initialized shared memory and * crash inside virtqueue_get_available_buffer (UNALIGNED on desc[garbage]). */ #define RPMSG_HANDSHAKE_ADDR ((volatile uint32_t *)(0x261C0000 0xF000)) #define RPMSG_HANDSHAKE_MAGIC (0xC0DEDA7AU) /* Send timeout (ms) - waits a short while if the master tx buffer pool is * temporarily exhausted (i.e. the remote has not yet recycled buffers). * Combined with the remote-side rx polling workaround this keeps the link * flowing without depending on the IPC notify interrupt path. */ #define RPMSG_SEND_TIMEOUT_MS (200U) /* Polling interval used as a workaround when the IPC notify interrupt is * not delivered reliably between cores. On the master side we poll tvq so * that any consumed-buffer notification path or remote replies are handled * even if the IPC interrupt doesnt fire. */ #define RPMSG_POLL_INTERVAL_MS (20U) static struct rpmsg_lite_instance *rpmsg_lite_dev RL_NULL; static struct rpmsg_lite_endpoint *rpmsg_ept RL_NULL; /* Master-side polling thread: drives both virtqueue callbacks directly so * that the link works without depending on cross-core IPC interrupts. The * tvq callback (rpmsg_lite_tx_callback) keeps link_state up to date; the * rvq callback (rpmsg_lite_rx_callback) processes any messages from the * remote side. */ static void rpmsg_poll_thread(void *parameter) { rt_kprintf([M33] vq polling thread started, interval%u ms\r\n, RPMSG_POLL_INTERVAL_MS); while (1) { if (rpmsg_lite_dev ! RL_NULL) { if (rpmsg_lite_dev-rvq ! RL_NULL) { virtqueue_notification(rpmsg_lite_dev-rvq); } if (rpmsg_lite_dev-tvq ! RL_NULL) { virtqueue_notification(rpmsg_lite_dev-tvq); } } rt_thread_mdelay(RPMSG_POLL_INTERVAL_MS); } } static void rpmsg_master_thread(void *parameter) { uint32_t counter 0; int32_t ret; rt_thread_t poll_tid; rt_kprintf([M33] Initializing rpmsg-lite master...\r\n); /* Pre-clear the handshake sentinel BEFORE master_init runs, so the * remote side cannot mistake stale shared memory for a ready signal * after a warm reset of M33 only. */ *RPMSG_HANDSHAKE_ADDR 0U; __DSB(); rpmsg_lite_dev rpmsg_lite_master_init(RPMSG_LITE_SHMEM_BASE, RPMSG_LITE_SHMEM_SIZE, RPMSG_LITE_LINK_ID, RL_NO_FLAGS); if (rpmsg_lite_dev RL_NULL) { rt_kprintf([M33] rpmsg_lite_master_init failed!\r\n); return; } rt_kprintf([M33] rpmsg-lite master initialized.\r\n); rpmsg_ept rpmsg_lite_create_ept(rpmsg_lite_dev, RPMSG_LITE_EPT_ADDR, RL_NULL, RL_NULL); if (rpmsg_ept RL_NULL) { rt_kprintf([M33] rpmsg_lite_create_ept failed!\r\n); return; } rt_kprintf([M33] rpmsg-lite endpoint created, addr%d.\r\n, RPMSG_LITE_EPT_ADDR); /* Publish the handshake magic AFTER vrings tx pool are fully ready. * The DSB before the store ensures all prior writes to the shared * vrings are globally visible before the magic becomes visible. */ __DSB(); *RPMSG_HANDSHAKE_ADDR RPMSG_HANDSHAKE_MAGIC; __DSB(); rt_kprintf([M33] handshake magic 0x%08x published at %p.\r\n, (unsigned int)RPMSG_HANDSHAKE_MAGIC, (void *)RPMSG_HANDSHAKE_ADDR); /* Start the polling workaround */ poll_tid rt_thread_create(rpmsg_p, rpmsg_poll_thread, RT_NULL, 1024, 9, 5); if (poll_tid ! RT_NULL) { rt_thread_startup(poll_tid); } else { rt_kprintf([M33] Failed to create polling thread!\r\n); } /* Wait for remote side link up */ while (!rpmsg_lite_is_link_up(rpmsg_lite_dev)) { rt_thread_mdelay(10); } rt_kprintf([M33] rpmsg-lite link is up.\r\n); while (1) { ret rpmsg_lite_send(rpmsg_lite_dev, rpmsg_ept, RPMSG_LITE_EPT_ADDR, (char *)counter, sizeof(counter), RPMSG_SEND_TIMEOUT_MS); if (ret RL_SUCCESS) { rt_kprintf([M33] sent counter %u\r\n, counter); counter; } else { rt_kprintf([M33] send failed, ret%d\r\n, ret); } rt_thread_mdelay(1000); } } int main(void) { rt_thread_t tid; rt_kprintf(Hello RT-Thread\r\n); rt_kprintf(This core is cortex-m33\r\n); rt_pin_mode(LED_PIN_B, PIN_MODE_OUTPUT); tid rt_thread_create(rpmsg_m, rpmsg_master_thread, RT_NULL, 2048, 10, 10); if (tid ! RT_NULL) { rt_thread_startup(tid); } else { rt_kprintf([M33] Failed to create rpmsg thread!\r\n); } while (1) { rt_kprintf(log from cortex-m33\r\n); rt_pin_write(LED_PIN_B, PIN_LOW); rt_thread_mdelay(1000); rt_pin_write(LED_PIN_B, PIN_HIGH); rt_thread_mdelay(1000); } return 0; }​五、M55 端Remote接收方关键设计M55 作为 Remote承担以下职责等待握手在调用rpmsg_lite_remote_init()之前先 spin 读取0x261CF000的 sentinel直到看到 magic 值。这是为了等待 M33 完成master_init对共享内存的零化和初始化。初始化与创建端点看到握手信号后再安全地调用rpmsg_lite_remote_init()和rpmsg_lite_create_ept()。Rx Polling 线程同样因为 IPC 中断不可靠启动轮询线程每隔 20ms 调用virtqueue_notification(rpmsg_lite_dev-rvq)主动检查是否有新消息到达。接收回调rpmsg_rx_callback中解析 payloaduint32_t counter并打印。完整代码#include rtthread.h #include rtdevice.h #include board.h #include rpmsg_lite.h #include virtqueue.h #define LED_PIN_G GET_PIN(16, 6) #define RPMSG_LITE_SHMEM_BASE ((void *)0x261C0000) #define RPMSG_LITE_LINK_ID RL_PLATFORM_PSE84_M33_M55_LINK_ID #define RPMSG_LITE_EPT_ADDR (30U) /* Boot-handshake sentinel - MUST match the master side. M55 boots/runs * faster than the M33 NS image, so without this guard the remote would * call rpmsg_lite_remote_init / start polling against a vring that has * never been zeroed by the master, read garbage out of avail-idx, and * hard-fault inside virtqueue_get_available_buffer when desc[garbage] * is dereferenced (UNALIGNED, r0/r4 garbage value). */ #define RPMSG_HANDSHAKE_ADDR ((volatile uint32_t *)(0x261C0000 0xF000)) #define RPMSG_HANDSHAKE_MAGIC (0xC0DEDA7AU) #define RPMSG_HANDSHAKE_POLL_MS (50U) #define RPMSG_HANDSHAKE_REPORT_MS (1000U) /* Polling interval used as a workaround when the IPC notify interrupt is * not delivered reliably between cores (e.g. when SRF or platform access * permissions block the rpmsg_platform notify path). 20 ms keeps latency * low while remaining cheap. */ #define RPMSG_POLL_INTERVAL_MS (20U) static struct rpmsg_lite_instance *rpmsg_lite_dev RL_NULL; static struct rpmsg_lite_endpoint *rpmsg_ept RL_NULL; static int32_t rpmsg_rx_callback(void *payload, uint32_t payload_len, uint32_t src, void *priv) { if (payload_len sizeof(uint32_t)) { uint32_t counter *(uint32_t *)payload; rt_kprintf([M55] received counter %u (from 0x%x)\r\n, counter, src); } else { rt_kprintf([M55] received unknown data, len%d\r\n, payload_len); } return RL_RELEASE; } /* Workaround thread: polls the receive virtqueue directly so that messages * placed in the avail ring by the master are processed even if the IPC * notification interrupt does not fire on this core. Calls into the same * code path that the platform ISR would normally trigger (env_isr - * virtqueue_notification - rpmsg_lite_rx_callback - ept-rx_cb). */ static void rpmsg_rx_poll_thread(void *parameter) { rt_kprintf([M55] rx polling thread started, interval%u ms\r\n, RPMSG_POLL_INTERVAL_MS); while (1) { if ((rpmsg_lite_dev ! RL_NULL) (rpmsg_lite_dev-rvq ! RL_NULL)) { virtqueue_notification(rpmsg_lite_dev-rvq); } rt_thread_mdelay(RPMSG_POLL_INTERVAL_MS); } } static void rpmsg_remote_thread(void *parameter) { rt_thread_t poll_tid; uint32_t waited_ms 0U; uint32_t magic 0U; /* Synchronize with the master before doing anything that touches the * shared rings. Spin (with cooperative sleep) until master_init has * published RPMSG_HANDSHAKE_MAGIC. Without this guard we observed a * hard fault (UNALIGNED, fault address 0xeefa5626) in the rx-poll * thread because virtqueue_get_available_buffer dereferenced * desc[garbage_idx] before the master had zeroed the vring. */ rt_kprintf([M55] waiting for master handshake at %p ...\r\n, (void *)RPMSG_HANDSHAKE_ADDR); for (;;) { __DSB(); magic *RPMSG_HANDSHAKE_ADDR; if (magic RPMSG_HANDSHAKE_MAGIC) { break; } rt_thread_mdelay(RPMSG_HANDSHAKE_POLL_MS); waited_ms RPMSG_HANDSHAKE_POLL_MS; if ((waited_ms % RPMSG_HANDSHAKE_REPORT_MS) 0U) { rt_kprintf([M55] still waiting for master, observed0x%08x, elapsed%u ms\r\n, (unsigned int)magic, (unsigned int)waited_ms); } } rt_kprintf([M55] master handshake observed after %u ms.\r\n, (unsigned int)waited_ms); rt_kprintf([M55] Initializing rpmsg-lite remote...\r\n); rpmsg_lite_dev rpmsg_lite_remote_init(RPMSG_LITE_SHMEM_BASE, RPMSG_LITE_LINK_ID, RL_NO_FLAGS); if (rpmsg_lite_dev RL_NULL) { rt_kprintf([M55] rpmsg_lite_remote_init failed!\r\n); return; } rt_kprintf([M55] rpmsg-lite remote initialized.\r\n); rpmsg_ept rpmsg_lite_create_ept(rpmsg_lite_dev, RPMSG_LITE_EPT_ADDR, rpmsg_rx_callback, RL_NULL); if (rpmsg_ept RL_NULL) { rt_kprintf([M55] rpmsg_lite_create_ept failed!\r\n); return; } rt_kprintf([M55] rpmsg-lite endpoint created, addr%d.\r\n, RPMSG_LITE_EPT_ADDR); /* Start the rx polling workaround */ poll_tid rt_thread_create(rpmsg_rx, rpmsg_rx_poll_thread, RT_NULL, 1024, 9, 5); if (poll_tid ! RT_NULL) { rt_thread_startup(poll_tid); } else { rt_kprintf([M55] Failed to create rx polling thread!\r\n); } while (1) { rt_thread_mdelay(1000); } } int main(void) { rt_thread_t tid; rt_kprintf(Hello RT-Thread\r\n); rt_kprintf(Its cortex-m55\r\n); rt_pin_mode(LED_PIN_G, PIN_MODE_OUTPUT); tid rt_thread_create(rpmsg_r, rpmsg_remote_thread, RT_NULL, 2048, 10, 10); if (tid ! RT_NULL) { rt_thread_startup(tid); } else { rt_kprintf([M55] Failed to create rpmsg thread!\r\n); } while (1) { rt_kprintf(log from cortex-m55\r\n); rt_pin_write(LED_PIN_G, PIN_LOW); rt_thread_mdelay(1000); rt_pin_write(LED_PIN_G, PIN_HIGH); rt_thread_mdelay(1000); } return 0; }​六、编译与烧录编译顺序与双核独立运行时相同先 M33后 M55。编译 M33 工程烧录编译 M55 工程烧录按 RST 复位或重新上电七、问题排查实录在调试过程中遇到了两个关键问题记录如下供读者参考。问题 1send failed, ret-5001现象M33 成功初始化后前两次rpmsg_lite_send成功之后持续报send failed, ret-5001即RL_ERR_NO_MEM。M55 端没有任何接收打印。原因M33 发送消息后需要通过 IPC notify 通知 M55 有新数据PSoC E84 的 IPC 中断路径存在可靠性问题可能与 SRF 配置或平台权限有关M55 收不到中断M55 未触发virtqueue_notification()- 未调用rpmsg_lite_rx_callback()- buffer 未被消费和释放M33 的 tx buffer pool 只有RL_BUFFER_COUNT默认 2个两次发送后就耗尽解决在 M33 和 M55 两侧都增加Polling 线程绕过 IPC 中断主动轮询 virtqueue/* M33 侧轮询 rvq tvq */ if (rpmsg_lite_dev-rvq ! RL_NULL) virtqueue_notification(rpmsg_lite_dev-rvq); if (rpmsg_lite_dev-tvq ! RL_NULL) virtqueue_notification(rpmsg_lite_dev-tvq); /* M55 侧轮询 rvq */ if (rpmsg_lite_dev-rvq ! RL_NULL) virtqueue_notification(rpmsg_lite_dev-rvq);​virtqueue_notification()是virtqueue.h公开的 API功能等价于触发一次该 vq 的 ISR 回调路径可以在用户代码中安全调用。问题 2M55 hard faultUNALIGNED地址0xeefa5626现象M55 启动 rx polling 线程后立即 hard fault。CFSR 显示UNALIGNED寄存器 r0/r4 的值都是0xeefa5626典型的未初始化内存垃圾值。根因这是启动时序竞争boot timing race。M55 内核启动速度远快于 M33NSM55 的rpmsg_remote_thread在几百毫秒内就创建并启动了 polling 线程但此时 M33 的rpmsg_lite_master_init()尚未执行共享内存0x261C0000起还是上电时的随机值virtqueue_notification()-virtqueue_get_available_buffer()读取avail-idx得到一个垃圾值如0xeefa5626用该垃圾值索引desc[]越界访问未初始化地址触发UNALIGNEDhard fault解决在共享内存末端增加**启动握手boot handshake**机制。M33 侧Master在master_init和create_ept全部成功之后再向约定地址写入 magic*RPMSG_HANDSHAKE_ADDR RPMSG_HANDSHAKE_MAGIC; /* 0xC0DEDA7A */​M55 侧Remote在调用rpmsg_lite_remote_init()之前先 spin 等待这个 magicwhile (*RPMSG_HANDSHAKE_ADDR ! RPMSG_HANDSHAKE_MAGIC) { rt_thread_mdelay(50); }​这样确保 M55 第一次读取 vring 时共享内存已经被 M33 完全初始化。为什么不在 M55 侧直接memset共享内存因为rpmsg_lite_master_init除了零化内存还要建立 desc 的 next 空闲链表、填充 used ring 等复杂结构。Remote 侧不具备这些初始化逻辑也不能与 Master 同时写共享内存。八、运行效果如果一切正常上电后串口输出应如下****************** PSOC Edge MCU: CM33 Secure Mode****************** PSRAM Cache is Enabled PSRAM init successful ****************** PSOC Edge MCU: CM33 Secure Mode Exit****************** ▒▒ \ | / - RT - Thread Operating System / | \ 5.0.2 build May 2 2026 16:24:37 2006 - 2022 Copyright by RT-Thread team Hello RT-Thread This core is cortex-m33 log from cortex-m33 [M33] Initializing rpmsg-lite master... [M33] rpmsg-lite master initialized. [M33] rpmsg-lite endpoint created, addr30. [M33] handshake magic 0xc0deda7a published at 0x261cf000. [M33] vq polling thread started, interval20 ms [M33] rpmsg-lite link is up. [M33] sent counter 0 [M55] master handshake observed after 50 ms. [M55] Initializing rpmsg-lite remote... [M55] rpmsg-lite remote initialized. [M55] rpmsg-lite endpoint created, addr30. [M55] rx polling thread started, interval20 ms [M55] received counter 0 (from 0x1e) [M33] sent counter 1 [M55] received counter 1 (from 0x1e) log from cortex-m55 log from cortex-m33 [M33] sent counter 2 [M55] received counter 2 (from 0x1e) [M33] sent counter 3 [M55] received counter 3 (from 0x1e) log from cortex-m55 log from cortex-m33 [M33] sent counter 4 [M55] received counter 4 (from 0x1e) [M33] sent counter 5 [M55] received counter 5 (from 0x1e)​九、总结本文在双核独立运行的基础上成功实现了 M33 - M55 的单向 rpmsg-lite 通信。核心经验如下要点说明启动顺序Secure M33 - M33NS使能 CM55 master_init- M55RemoteIPC 不可靠PSoC E84 的跨核 IPC notify 不够稳定需用 polling 线程绕过时序竞争M55 启动快于 M33必须用 sentinel 握手机制避免读取未初始化共享内存只改用户层所有 workaround 均放在applications/main.c不动packages/rpmsg-lite/超时发送Master 侧发送使用RPMSG_SEND_TIMEOUT_MS而非RL_DONT_BLOCK配合 polling 自动恢复后续可在此基础上扩展更复杂的双核交互例如 M55 回复 ACK、使用 rpmsg 命名服务rpmsg_ns动态发现端点等。十、参考资料序号资源说明1RT-Thread 软件包 - rpmsg-lite官方软件包页面包含完整的中文文档组件优势、配置选项、API 用法2GitHub - flyingcys/rpmsg-liteNXP RPMsg-Lite 在 RT-Thread 生态中的 fork源码与上游同步3RT-Thread 问答社区 - rpmsg-lite 多核通信原理分析详尽的通信流程图解初始化、发送、接收的完整调用链4微信公众号 - 基于 RT-Thread 的 RPMsg-Lite 异构多核通信原理分析与资料 3 同源便于手机端阅读rpmsg-lite 核心知识点摘要以下整理自上述参考资料供快速查阅1. 设计动机RPMsg-Lite 由 NXP 开发相比 OpenAMP 的 RPMsg 实现优势在于更小的代码体积和更简化的 API。对于资源受限的 Cortex-M 系列 MCU这是更优选择组件/配置Flash (B)RAM (B)OpenAMP RPMsg5547456 动态分配RPMsg-Lite / 动态 API346256 动态分配RPMsg-Lite / 静态 API无 malloc29263522. 发送流程rpmsg_lite_send - rpmsg_lite_format_message - virtqueue_kick - vq_ring_notify_host - virtqueue_notify - platform_notify (触发 IPC 中断通知对端)​对端收到 IPC 中断后env_isr - virtqueue_notification - rpmsg_lite_rx_callback - ept-rx_cb (用户注册的回调函数)​3. 接收流程基于回调在 RTOS 环境下推荐的方式是为每个 endpoint 注册独立的rx_cb回调。当对端发送数据时platform_notify()触发本核 IPC 中断ISR 中调用env_isr()进而调用virtqueue_notification()virtqueue_notification()触发rpmsg_lite_rx_callback()在rpmsg_lite_rx_callback()中遍历 endpoint 列表找到匹配的ept-rx_cb并调用用户在回调中处理接收到的数据返回RL_RELEASE释放 buffer 或RL_HOLD持有 buffer4. 关键配置选项配置项默认值说明RL_BUFFER_COUNT2共享内存中 buffer 数量必须是 2 的幂RL_BUFFER_PAYLOAD_SIZE496单个 buffer 有效载荷大小必须是2^n - 16RL_API_HAS_ZEROCOPY1启用零拷贝 APIrpmsg_lite_send_nocopy等RL_USE_STATIC_API0静态 API 开关禁用动态内存分配RL_ALLOW_CONSUMED_BUFFERS_NOTIFICATION0每次消费 buffer 后是否通知对端5. 共享内存要求必须配置为Non-Cacheable不可缓存内存建议在链接器脚本中定义专用的共享内存段必须确保应用的其他部分不会意外访问该区域6. 关于virtqueue_notification()这是virtqueue.h中公开的 API非内部函数其本质是直接调用vq-callback_fc(vq)。在本教程的 Polling workaround 中正是利用这一特性在用户线程中主动驱动 vq 回调从而绕过不可靠的 IPC 中断路径。。---------------------作者HonestQiao链接https://bbs.21ic.com/icview-3515217-1-1.html来源21ic.com此文章已获得原创/原创奖标签著作权归21ic所有任何人未经允许禁止转载。